This invention relates to bending glass sheets and particularly to bending glass sheets to sharp or V-bends in which the line of bending is curved. By way of definition for the sake of this disclosure, a sharp bend is defined as one in which the radius of bend does not exceed 8 inches (approximately 20 cm.).
Glass sheets have been bent by the sag bending method by mounting one or more glass sheets on an outline metal mold of the skeleton type having a curvature in elevation and an outline configuration conforming to the shape desired for the glass sheet or sheets after bending. The mold laden with one or more glass sheets is introduced into a furnace where the glass sheets are heated to the glass deformation temperature and sag to conform to the upper surface of the mold. Glass sheets have also been bent to sharp curvatures by combining the overall heat in an enclosed furnace with localized heat applied along one or more lines to be sharply bent. This localized heat radiates either from an elongated heating element closely spaced to each line of sharp bending of the glass or from one or more lines of electroconductive material applied to the glass surface along each line of sharp bending.
In the past, the lines of sharp bending have been limited to straight lines. Recently, automobile stylists have requested that glass sheets be provided for possible use in future models of automobiles of advanced design. The design requires a glass sheet bent about an elongated curved axis of bending so as to be incorporated in a highly styled automobile of the future where the curved line of bending of the glass merges into a curved line of bending between a roof and a side portion of the automobile body. Apparatus available in the prior art is not capable of bending glass sheets into such shapes.